The present invention relates to the oscillation of a bar code reader mirror which reflects scanning light. In particular, the present invention relates to the electric oscillator which oscillates a bar code reader mirror to create the horizontal scanning motion of the reader's scanning light beam along an axis (e.g. horizontal axis).
An important consideration in designing bar code readers is the design of the structure for oscillating the mirror(s) of such a reader. More specifically, mirrors in stationary industrial bar code readers typically oscillate at frequencies in the range of 100-500 Hz. An important consideration in designing such structures is reducing the energy required to oscillate mirrors at these frequencies. Accordingly, the design of bearing and spring structures which support reader mirrors is directed to reducing the force required to oscillate the mirror, while also ensuring that the spring and bearing assemblies are able to withstand between 15-45 billion cycles. However, typical magnetic oscillating arrangements introduce forces into such bearing and spring structures which tend to reduce the life thereof.
In addition to reducing the life of the springs and bearings supporting a reader mirror, an improperly configured motor will unnecessarily consume energy and generate heat within the reader housing. This heat must be dissipated to reduce the risk of heat damage to the other components of the scanner. Under certain circumstances, heat generation and heat dissipation require that the relative size of the reader housing be increased to reduce the risk of heat damage.
In view of the problems created by typically used magnetic oscillating arrangements, it would be desirable to produce a magnetic oscillating arrangement for a reader mirror configured to create forces having amplitudes and directions designed to direct substantially all of the energy applied to the oscillator into the production of oscillatory motion. Additionally, it would be advantageous to provide a magnetic oscillating arrangement which generates wider oscillation angles at higher frequencies.